Genome-Wide Identification and Characterization of HSP70 Gene Family in Aquilaria sinensis (Lour.) Gilg

Abstract

The heat shock protein 70 (<i>HSP70</i>) gene family perform a fundamental role in protecting plants against biotic and abiotic stresses. <i>Aquilaria sinensis</i> is a classic stress-induced medicinal plant, producing a valuable dark resin in a wood matrix, known as agarwood, in response to environmental stresses. The <i>HSP70</i> gene family has been systematic identified in many plants, but there is no comprehensive analysis at the genomic level in <i>A. sinensis</i>. In this study, 15 putative <i>HSP70</i> genes were identified in <i>A. sinensis</i> through genome-wide bioinformatics analysis. Based on their phylogenetic relationships, the 15 <i>AsHSP70</i> were grouped into six sub-families that with the conserved motifs and gene structures, and the genes were mapped onto six separate linkage groups. A qRT-PCR analysis showed that the relative expression levels of all the <i>AsHSP70</i> genes were up-regulated by heat stress. Subcellular localization of all HSP70s was predicted, and three were verified by transiently expressed in <i>Arabidopsis</i> protoplasts. Based on the expression profiles in different tissues and different layers treated with Agar-Wit, we predict <i>AsHSP70</i> genes are involved in different stages of agarwood formation. The systematic identification and expression analysis of <i>HSP70s</i> gene family imply some of them may play important roles in the formation of agarwood. Our findings not only provide a foundation for further study their biological function in the later research in <i>A. sinensis</i>, but also provides a reference for the analysis of HSPs in other species.